Merge pull request #34 from crocs-muni/feat/deterministic-prng

Support deterministic PRNG where possible.

32 files changed, 521 insertions, 193 deletions

diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/ECTesterStandalone.java b/standalone/src/main/java/cz/crcs/ectester/standalone/ECTesterStandalone.java
index 4f76639..04537f0 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/ECTesterStandalone.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/ECTesterStandalone.java
@@ -31,6 +31,7 @@ import cz.crcs.ectester.common.test.TestException;
 import cz.crcs.ectester.common.util.ByteUtil;
 import cz.crcs.ectester.common.util.ECUtil;
 import cz.crcs.ectester.common.util.FileUtil;
+import cz.crcs.ectester.common.util.Util;
 import cz.crcs.ectester.data.EC_Store;
 import cz.crcs.ectester.standalone.consts.KeyAgreementIdent;
 import cz.crcs.ectester.standalone.consts.KeyPairGeneratorIdent;
@@ -104,12 +105,52 @@ public class ECTesterStandalone {
 
             if (!System.getProperty("os.name").startsWith("Windows")) {
                 FileUtil.write(LIB_RESOURCE_DIR + "lib_timing.so", reqs.resolve("lib_timing.so"));
-                System.load(reqs.resolve("lib_timing.so").toString());
-
+                FileUtil.write(LIB_RESOURCE_DIR + "lib_preload.so", reqs.resolve("lib_preload.so"));
+                FileUtil.write(LIB_RESOURCE_DIR + "lib_prng.so", reqs.resolve("lib_prng.so"));
                 FileUtil.write(LIB_RESOURCE_DIR + "lib_csignals.so", reqs.resolve("lib_csignals.so"));
-                System.load(reqs.resolve("lib_csignals.so").toString());
                 FileUtil.write(LIB_RESOURCE_DIR + "lib_cppsignals.so", reqs.resolve("lib_cppsignals.so"));
-                System.load(reqs.resolve("lib_cppsignals.so").toString());
+
+                String preloadLibPath = reqs.resolve("lib_preload.so").toAbsolutePath().toString();
+                String preload = System.getenv("LD_PRELOAD");
+                if (preload == null && !cli.hasOption("no-preload")) {
+                    ProcessBuilder builder = new ProcessBuilder();
+                    Map<String, String> env = builder.environment();
+                    env.put("LD_PRELOAD", preloadLibPath);
+
+                    ProcessHandle.Info info = ProcessHandle.current().info();
+                    List<String> argList = new LinkedList<>();
+                    if (info.command().isPresent()) {
+                        argList.add(info.command().get());
+                    } else {
+                        System.err.println("Cannot locate command to spawn preloaded-subprocess.");
+                        return;
+                    }
+                    if (info.arguments().isPresent()) {
+                        argList.addAll(List.of(info.arguments().get()));
+                    } else {
+                        System.err.println("Cannot locate arguments to spawn preloaded-subprocess.");
+                        return;
+                    }
+                    builder.command(argList);
+                    builder.inheritIO();
+
+                    Process process = builder.start();
+                    int result;
+                    while (true) {
+                        try {
+                            result = process.waitFor();
+                            break;
+                        } catch (InterruptedException ignored) {
+                        }
+                    }
+                    System.exit(result);
+                } else {
+                    // Load the utility libs.
+                    System.load(reqs.resolve("lib_prng.so").toString());
+                    System.load(reqs.resolve("lib_timing.so").toString());
+                    System.load(reqs.resolve("lib_csignals.so").toString());
+                    System.load(reqs.resolve("lib_cppsignals.so").toString());
+                }
             }
 
             List<ProviderECLibrary> libObjects = new LinkedList<>();
@@ -191,7 +232,15 @@ public class ECTesterStandalone {
         Option output = Option.builder("o").longOpt("output").desc("Output into file <output_file>. The file can be prefixed by the format (one of text,yml,xml), such as: xml:<output_file>.").hasArgs().argName("output_file").optionalArg(false).numberOfArgs(1).build();
         Option outputRaw = Option.builder("o").longOpt("output").desc("Output CSV into file <output_file>.").hasArgs().argName("output_file").optionalArg(false).numberOfArgs(1).build();
         Option quiet = Option.builder("q").longOpt("quiet").desc("Do not output to stdout.").build();
-        Option timeSource = Option.builder("ts").longOpt("time-source").desc("Use a given native timing source: {rdtsc, monotonic, monotonic-raw, cputime-process, cputime-thread, perfcount}").hasArgs().argName("source").optionalArg(false).numberOfArgs(1).build();
+        Option timeSource = Option.builder("ts").longOpt("time-source").desc("Use a given native timing source: {rdtsc, monotonic, monotonic-raw, cputime-process, cputime-thread}").hasArgs().argName("source").optionalArg(false).numberOfArgs(1).build();
+        Option prngSeed = Option.builder("ps").longOpt("prng-seed").desc("Use a deterministic PRNG with the given [seed] (hexadecimal) in the library.").hasArgs().argName("seed").optionalArg(false).numberOfArgs(1).build();
+        Option file = Option.builder("f").longOpt("file").hasArg().argName("file").optionalArg(false).desc("Input [file] to sign.").build();
+        Option message = Option.builder("d").longOpt("data").desc("Sign the given [message].").hasArgs().argName("message").optionalArg(false).numberOfArgs(1).build();
+        Option messageSeed = Option.builder("ds").longOpt("data-seed").desc("Use a deterministic PRNG with the given [seed] (hexadecimal) to generate the messages.").hasArgs().argName("seed").optionalArg(false).numberOfArgs(1).build();
+        OptionGroup ecdsaMessage = new OptionGroup();
+        ecdsaMessage.addOption(file);
+        ecdsaMessage.addOption(message);
+        ecdsaMessage.addOption(messageSeed);
 
         Options testOpts = new Options();
         testOpts.addOption(bits);
@@ -199,6 +248,7 @@ public class ECTesterStandalone {
         testOpts.addOption(curveName);
         testOpts.addOption(output);
         testOpts.addOption(quiet);
+        testOpts.addOption(prngSeed);
         testOpts.addOption(Option.builder("gt").longOpt("kpg-type").desc("Set the KeyPairGenerator object [type].").hasArg().argName("type").optionalArg(false).build());
         testOpts.addOption(Option.builder("kt").longOpt("ka-type").desc("Set the KeyAgreement object [type].").hasArg().argName("type").optionalArg(false).build());
         testOpts.addOption(Option.builder("st").longOpt("sig-type").desc("Set the Signature object [type].").hasArg().argName("type").optionalArg(false).build());
@@ -215,6 +265,7 @@ public class ECTesterStandalone {
         ecdhOpts.addOption(curveName);
         ecdhOpts.addOption(outputRaw);
         ecdhOpts.addOption(timeSource);
+        ecdhOpts.addOption(prngSeed);
         ecdhOpts.addOption(Option.builder("t").longOpt("type").desc("Set KeyAgreement object [type].").hasArg().argName("type").optionalArg(false).build());
         ecdhOpts.addOption(Option.builder().longOpt("key-type").desc("Set the key [algorithm] for which the key should be derived in KeyAgreements with KDF. Default is \"AES\".").hasArg().argName("algorithm").optionalArg(false).build());
         ecdhOpts.addOption(Option.builder("n").longOpt("amount").hasArg().argName("amount").optionalArg(false).desc("Do ECDH [amount] times.").build());
@@ -231,12 +282,13 @@ public class ECTesterStandalone {
         ecdsaOpts.addOption(curveName);
         ecdsaOpts.addOption(outputRaw);
         ecdsaOpts.addOption(timeSource);
+        ecdsaOpts.addOption(prngSeed);
         ecdsaOpts.addOptionGroup(privateKey);
         ecdsaOpts.addOptionGroup(publicKey);
         ecdsaOpts.addOption(Option.builder().longOpt("fixed").desc("Perform all ECDSA with fixed keypair.").build());
         ecdsaOpts.addOption(Option.builder("t").longOpt("type").desc("Set Signature object [type].").hasArg().argName("type").optionalArg(false).build());
         ecdsaOpts.addOption(Option.builder("n").longOpt("amount").hasArg().argName("amount").optionalArg(false).desc("Do ECDSA [amount] times.").build());
-        ecdsaOpts.addOption(Option.builder("f").longOpt("file").hasArg().argName("file").optionalArg(false).desc("Input [file] to sign.").build());
+        ecdsaOpts.addOptionGroup(ecdsaMessage);
         ParserOptions ecdsa = new ParserOptions(new DefaultParser(), ecdsaOpts, "Perform EC based Signature.");
         actions.put("ecdsa", ecdsa);
 
@@ -246,6 +298,7 @@ public class ECTesterStandalone {
         generateOpts.addOption(curveName);
         generateOpts.addOption(outputRaw);
         generateOpts.addOption(timeSource);
+        generateOpts.addOption(prngSeed);
         generateOpts.addOption(Option.builder("n").longOpt("amount").hasArg().argName("amount").optionalArg(false).desc("Generate [amount] of EC keys.").build());
         generateOpts.addOption(Option.builder("t").longOpt("type").hasArg().argName("type").optionalArg(false).desc("Set KeyPairGenerator object [type].").build());
         ParserOptions generate = new ParserOptions(new DefaultParser(), generateOpts, "Generate EC keypairs.");
@@ -283,6 +336,7 @@ public class ECTesterStandalone {
         opts.addOption(Option.builder("V").longOpt("version").desc("Print version info.").build());
         opts.addOption(Option.builder("h").longOpt("help").desc("Print help(about <command>).").hasArg().argName("command").optionalArg(true).build());
         opts.addOption(Option.builder("C").longOpt("color").desc("Print stuff with color, requires ANSI terminal.").build());
+        opts.addOption(Option.builder().longOpt("no-preload").desc("Do not use LD_PRELOAD.").build());
 
         return optParser.parse(opts, args);
     }
@@ -307,6 +361,7 @@ public class ECTesterStandalone {
                 System.out.println(Colors.bold("\t\t- Fullname: ") + lib.getProvider().getName());
                 System.out.println(Colors.bold("\t\t- Version: ") + lib.getProvider().getVersionStr());
                 System.out.println(Colors.bold("\t\t- Supports native timing: ") + lib.getNativeTimingSupport().toString());
+                System.out.println(Colors.bold("\t\t- Supports deterministic PRNG: ") + lib.supportsDeterministicPRNG());
                 Set<KeyPairGeneratorIdent> kpgs = lib.getKPGs();
                 if (!kpgs.isEmpty()) {
                     System.out.println(Colors.bold("\t\t- KeyPairGenerators: ") + kpgs.stream().map(KeyPairGeneratorIdent::getName).sorted().collect(Collectors.joining(", ")));
@@ -409,12 +464,25 @@ public class ECTesterStandalone {
             throw new NoSuchAlgorithmException(algo);
         }
 
+        SecureRandom random;
+        if (cli.hasOption("ecdh.prng-seed")) {
+            String seedString = cli.getOptionValue("ecdh.prng-seed");
+            byte[] seed = ByteUtil.hexToBytes(seedString, true);
+            random = Util.getRandom(seed);
+            if (!lib.setupDeterministicPRNG(seed)) {
+                System.err.println("Couldn't set PRNG seed.");
+                return;
+            }
+        } else {
+            random = new SecureRandom();
+        }
+
         KeyAgreement ka = kaIdent.getInstance(lib.getProvider());
         KeyPairGenerator kpg = kpIdent.getInstance(lib.getProvider());
         AlgorithmParameterSpec spec = null;
         if (cli.hasOption("ecdh.bits")) {
             int bits = Integer.parseInt(cli.getOptionValue("ecdh.bits"));
-            kpg.initialize(bits);
+            kpg.initialize(bits, random);
         } else if (cli.hasOption("ecdh.named-curve")) {
             String curveName = cli.getOptionValue("ecdh.named-curve");
             EC_Curve curve = EC_Store.getInstance().getObject(EC_Curve.class, curveName);
@@ -423,11 +491,15 @@ public class ECTesterStandalone {
                 return;
             }
             spec = curve.toSpec();
-            kpg.initialize(spec);
+            kpg.initialize(spec, random);
         } else if (cli.hasOption("ecdh.curve-name")) {
             String curveName = cli.getOptionValue("ecdh.curve-name");
             spec = new ECGenParameterSpec(curveName);
-            kpg.initialize(spec);
+            kpg.initialize(spec, random);
+        } else if (cli.hasOption("ecdh.prng-seed") && !(lib instanceof NativeECLibrary)) {
+            // TODO: This only happens if at least one of the (pubkey and privkey) needs to be generated.
+            System.err.println("Unable to pass PRNG seed to a non-native library without specifying either key-size, named curve or curve name options.");
+            return;
         }
 
         if (cli.hasOption("ecdh.time-source")) {
@@ -483,9 +555,9 @@ public class ECTesterStandalone {
 
             long elapsed = -System.nanoTime();
             if (spec instanceof ECParameterSpec && lib instanceof NativeECLibrary) {
-                ka.init(privkey, spec);
+                ka.init(privkey, spec, random);
             } else {
-                ka.init(privkey);
+                ka.init(privkey, random);
             }
             ka.doPhase(pubkey, true);
             elapsed += System.nanoTime();
@@ -519,8 +591,24 @@ public class ECTesterStandalone {
      *
      */
     private void ecdsa() throws NoSuchAlgorithmException, InvalidAlgorithmParameterException, InvalidKeyException, IOException, SignatureException {
-        byte[] data;
-        String dataString;
+        ProviderECLibrary lib = cfg.selected;
+
+        SecureRandom random;
+        if (cli.hasOption("ecdsa.prng-seed")) {
+            String seedString = cli.getOptionValue("ecdsa.prng-seed");
+            byte[] seed = ByteUtil.hexToBytes(seedString, true);
+            random = Util.getRandom(seed);
+            if (!lib.setupDeterministicPRNG(seed)) {
+                System.err.println("Couldn't set PRNG seed.");
+                return;
+            }
+        } else {
+            random = new SecureRandom();
+        }
+
+        byte[] data = null;
+        String dataString = null;
+        SecureRandom dataRandom = null;
         if (cli.hasOption("ecdsa.file")) {
             String fileName = cli.getOptionValue("ecdsa.file");
             File in = new File(fileName);
@@ -530,13 +618,17 @@ public class ECTesterStandalone {
             }
             data = Files.readAllBytes(in.toPath());
             dataString = "";
+        } else if (cli.hasOption("ecdsa.data")) {
+            dataString = cli.getOptionValue("ecdsa.data");
+            data = ByteUtil.hexToBytes(dataString);
+        } else if (cli.hasOption("ecdsa.data-seed")) {
+            String seedString = cli.getOptionValue("ecdsa.prng-seed");
+            byte[] seed = ByteUtil.hexToBytes(seedString, true);
+            dataRandom = Util.getRandom(seed);
         } else {
-            Random random = new Random();
-            data = new byte[32];
-            random.nextBytes(data);
-            dataString = ByteUtil.bytesToHex(data, false);
+            dataRandom = new SecureRandom();
         }
-        ProviderECLibrary lib = cfg.selected;
+
         String algo = cli.getOptionValue("ecdsa.type", "ECDSA");
         SignatureIdent sigIdent = lib.getSigs().stream()
                 .filter((ident) -> ident.contains(algo))
@@ -571,7 +663,7 @@ public class ECTesterStandalone {
         ECParameterSpec spec = null;
         if (cli.hasOption("ecdsa.bits")) {
             int bits = Integer.parseInt(cli.getOptionValue("ecdsa.bits"));
-            kpg.initialize(bits);
+            kpg.initialize(bits, random);
         } else if (cli.hasOption("ecdsa.named-curve")) {
             String curveName = cli.getOptionValue("ecdsa.named-curve");
             EC_Curve curve = EC_Store.getInstance().getObject(EC_Curve.class, curveName);
@@ -580,10 +672,14 @@ public class ECTesterStandalone {
                 return;
             }
             spec = curve.toSpec();
-            kpg.initialize(spec);
+            kpg.initialize(spec, random);
         } else if (cli.hasOption("ecdsa.curve-name")) {
             String curveName = cli.getOptionValue("ecdsa.curve-name");
-            kpg.initialize(new ECGenParameterSpec(curveName));
+            kpg.initialize(new ECGenParameterSpec(curveName), random);
+        } else if (cli.hasOption("ecdsa.prng-seed") && !(lib instanceof NativeECLibrary)) {
+            // TODO: This only happens if at least one of the (pubkey and privkey) needs to be generated.
+            System.err.println("Unable to pass PRNG seed to a non-native library without specifying either key-size, named curve or curve name options.");
+            return;
         }
 
         if (cli.hasOption("ecdsa.time-source")) {
@@ -636,7 +732,12 @@ public class ECTesterStandalone {
                 }
             }
 
-            sig.initSign(privkey);
+            if (dataRandom != null) {
+                data = dataRandom.generateSeed(16);
+                dataString = ByteUtil.bytesToHex(data, false);
+            }
+
+            sig.initSign(privkey, random);
             sig.update(data);
 
             long signTime = -System.nanoTime();
@@ -705,10 +806,24 @@ public class ECTesterStandalone {
         if (ident == null) {
             throw new NoSuchAlgorithmException(algo);
         }
+
+        SecureRandom random;
+        if (cli.hasOption("generate.prng-seed")) {
+            String seedString = cli.getOptionValue("generate.prng-seed");
+            byte[] seed = ByteUtil.hexToBytes(seedString, true);
+            random = Util.getRandom(seed);
+            if (!lib.setupDeterministicPRNG(seed)) {
+                System.err.println("Couldn't set PRNG seed.");
+                return;
+            }
+        } else {
+            random = new SecureRandom();
+        }
+
         KeyPairGenerator kpg = ident.getInstance(lib.getProvider());
         if (cli.hasOption("generate.bits")) {
             int bits = Integer.parseInt(cli.getOptionValue("generate.bits"));
-            kpg.initialize(bits);
+            kpg.initialize(bits, random);
         } else if (cli.hasOption("generate.named-curve")) {
             String curveName = cli.getOptionValue("generate.named-curve");
             EC_Curve curve = EC_Store.getInstance().getObject(EC_Curve.class, curveName);
@@ -716,10 +831,13 @@ public class ECTesterStandalone {
                 System.err.println("Curve not found: " + curveName);
                 return;
             }
-            kpg.initialize(curve.toSpec());
+            kpg.initialize(curve.toSpec(), random);
         } else if (cli.hasOption("generate.curve-name")) {
             String curveName = cli.getOptionValue("generate.curve-name");
-            kpg.initialize(new ECGenParameterSpec(curveName));
+            kpg.initialize(new ECGenParameterSpec(curveName), random);
+        } else if (cli.hasOption("generate.prng-seed") && !(lib instanceof NativeECLibrary)) {
+            System.err.println("Unable to pass PRNG seed to a non-native library without specifying either key-size, named curve or curve name options.");
+            return;
         }
 
         if (cli.hasOption("generate.time-source")) {
@@ -818,6 +936,16 @@ public class ECTesterStandalone {
             testTo = -1;
         }
 
+        ProviderECLibrary lib = cfg.selected;
+        if (cli.hasOption("test.prng-seed")) {
+            String seedString = cli.getOptionValue("test.prng-seed");
+            byte[] seed = ByteUtil.hexToBytes(seedString, true);
+            if (!lib.setupDeterministicPRNG(seed)) {
+                System.err.println("Couldn't set PRNG seed.");
+                return;
+            }
+        }
+
         switch (testSuite) {
             case "test-vectors":
                 suite = new StandaloneTestVectorSuite(writer, cfg, cli);
@@ -997,6 +1125,15 @@ public class ECTesterStandalone {
                 }
             }
 
+            if (cli.isNext("generate") || cli.isNext("ecdh") || cli.isNext("ecdsa") || cli.isNext("test")) {
+                if (cli.hasOption(next + ".prng-seed")) {
+                    if (!selected.supportsDeterministicPRNG()) {
+                        System.err.printf("Deterministic PRNG is not supported by library %s.%n", selected.name());
+                        return false;
+                    }
+                }
+            }
+
             return true;
         }
     }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BoringsslLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BoringsslLib.java
index af4d969..06e6b4a 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BoringsslLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BoringsslLib.java
@@ -16,4 +16,10 @@ public class BoringsslLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public boolean supportsDeterministicPRNG() {
+        // This is provided by the native preload that hooks all randomness sources.
+        return true;
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BotanLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BotanLib.java
index e8f6e13..c072e84 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BotanLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BotanLib.java
@@ -17,4 +17,10 @@ public class BotanLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BouncyCastleLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BouncyCastleLib.java
index e8a4d30..0a7ea8c 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BouncyCastleLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/BouncyCastleLib.java
@@ -25,4 +25,16 @@ public class BouncyCastleLib extends ProviderECLibrary {
         }
         return result;
     }
+
+    @Override
+    public boolean supportsDeterministicPRNG() {
+        return true;
+    }
+
+    @Override
+    public boolean setupDeterministicPRNG(byte[] seed) {
+        // This is done by passing the SecureRandom into the individual KeyPairGenerator, KeyAgreement and Signature
+        // instances. Thus, this does nothing.
+        return true;
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/CryptoppLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/CryptoppLib.java
index 66aa9ea..25f2de4 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/CryptoppLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/CryptoppLib.java
@@ -17,4 +17,10 @@ public class CryptoppLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/GcryptLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/GcryptLib.java
index 83d78ef..d1452a9 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/GcryptLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/GcryptLib.java
@@ -17,4 +17,10 @@ public class GcryptLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public boolean supportsDeterministicPRNG() {
+        // This is provided by the native preload that hooks all randomness sources.
+        return true;
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/IppcpLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/IppcpLib.java
index 115fe00..fa51585 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/IppcpLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/IppcpLib.java
@@ -17,4 +17,10 @@ public class IppcpLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/LibresslLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/LibresslLib.java
index 2dba049..e53399c 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/LibresslLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/LibresslLib.java
@@ -16,4 +16,10 @@ public class LibresslLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public boolean supportsDeterministicPRNG() {
+        // This is provided by the native preload that hooks all randomness sources.
+        return true;
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/MbedTLSLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/MbedTLSLib.java
index e44598c..efc8cad 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/MbedTLSLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/MbedTLSLib.java
@@ -17,4 +17,10 @@ public class MbedTLSLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NativeECLibrary.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NativeECLibrary.java
index c11dbdb..fb4e430 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NativeECLibrary.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NativeECLibrary.java
@@ -86,5 +86,8 @@ public abstract class NativeECLibrary extends ProviderECLibrary {
     @Override
     public native long getLastNativeTiming();
 
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
+
     abstract Provider createProvider();
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NettleLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NettleLib.java
index d4df414..aa90c38 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NettleLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/NettleLib.java
@@ -49,4 +49,10 @@ public class NettleLib extends NativeECLibrary {
         }
         throw new InvalidAlgorithmParameterException("Unknown curve.");
     }
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/OpensslLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/OpensslLib.java
index 61f00a4..69c84bc 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/OpensslLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/OpensslLib.java
@@ -16,4 +16,10 @@ public class OpensslLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/ProviderECLibrary.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/ProviderECLibrary.java
index d9d6749..a9178f6 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/ProviderECLibrary.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/ProviderECLibrary.java
@@ -69,21 +69,29 @@ public abstract class ProviderECLibrary implements ECLibrary {
     }
 
     public boolean setNativeTimingType(String type) {
-    	return false;
+        return false;
     }
 
     public long getNativeTimingResolution() {
         return 0;
     }
 
-	public String getNativeTimingUnit() {
-		return null;
-	}
+    public String getNativeTimingUnit() {
+        return null;
+    }
 
     public long getLastNativeTiming() {
         return 0;
     }
 
+    public boolean supportsDeterministicPRNG() {
+        return false;
+    }
+
+    public boolean setupDeterministicPRNG(byte[] seed) {
+        return false;
+    }
+
     @Override
     public Set<KeyAgreementIdent> getKAs() {
         return getIdents("KeyAgreement", KeyAgreementIdent::get);
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/SunECLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/SunECLib.java
index 7209dc3..c38300d 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/SunECLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/SunECLib.java
@@ -25,4 +25,16 @@ public class SunECLib extends ProviderECLibrary {
         }
         return result;
     }
+
+    @Override
+    public boolean supportsDeterministicPRNG() {
+        return true;
+    }
+
+    @Override
+    public boolean setupDeterministicPRNG(byte[] seed) {
+        // This is done by passing the SecureRandom into the individual KeyPairGenerator, KeyAgreement and Signature
+        // instances. Thus, this does nothing.
+        return true;
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/TomcryptLib.java b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/TomcryptLib.java
index 8c000a2..e499451 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/libs/TomcryptLib.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/libs/TomcryptLib.java
@@ -17,4 +17,10 @@ public class TomcryptLib extends NativeECLibrary {
 
     @Override
     public native Set<String> getCurves();
+
+    @Override
+    public native boolean supportsDeterministicPRNG();
+
+    @Override
+    public native boolean setupDeterministicPRNG(byte[] seed);
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/output/TextTestWriter.java b/standalone/src/main/java/cz/crcs/ectester/standalone/output/TextTestWriter.java
index 13a9e72..c3ddea5 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/output/TextTestWriter.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/output/TextTestWriter.java
@@ -4,6 +4,7 @@ import cz.crcs.ectester.common.cli.Colors;
 import cz.crcs.ectester.common.output.BaseTextTestWriter;
 import cz.crcs.ectester.common.test.TestSuite;
 import cz.crcs.ectester.common.test.Testable;
+import cz.crcs.ectester.common.util.ByteUtil;
 import cz.crcs.ectester.standalone.ECTesterStandalone;
 import cz.crcs.ectester.standalone.test.base.StandaloneTestable;
 import cz.crcs.ectester.standalone.test.suites.StandaloneTestSuite;
@@ -47,7 +48,8 @@ public class TextTestWriter extends BaseTextTestWriter {
         if (suite instanceof StandaloneTestSuite) {
             StandaloneTestSuite standaloneSuite = (StandaloneTestSuite) suite;
             String sb = "═══ " + Colors.underline("ECTester version:") + " " + ECTesterStandalone.VERSION + System.lineSeparator() +
-                    "═══ " + Colors.underline("Library:") + " " + standaloneSuite.getLibrary().fullName() + System.lineSeparator();
+                    "═══ " + Colors.underline("Library:") + " " + standaloneSuite.getLibrary().fullName() + System.lineSeparator() +
+                    "═══ " + Colors.underline("Seed:") + " " + ByteUtil.bytesToHex(standaloneSuite.getSeed()) + System.lineSeparator();
             return sb;
         }
         return "";
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/output/XMLTestWriter.java b/standalone/src/main/java/cz/crcs/ectester/standalone/output/XMLTestWriter.java
index 2341fc7..06e7399 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/output/XMLTestWriter.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/output/XMLTestWriter.java
@@ -149,6 +149,10 @@ public class XMLTestWriter extends BaseXMLTestWriter {
             Element name = doc.createElement("name");
             name.setTextContent(standaloneSuite.getLibrary().fullName());
             result.appendChild(name);
+
+            Element seed = doc.createElement("seed");
+            seed.setTextContent(ByteUtil.bytesToHex(standaloneSuite.getSeed()));
+            result.appendChild(seed);
             return result;
         }
         return null;
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/output/YAMLTestWriter.java b/standalone/src/main/java/cz/crcs/ectester/standalone/output/YAMLTestWriter.java
index 66c5e38..d22c441 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/output/YAMLTestWriter.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/output/YAMLTestWriter.java
@@ -117,6 +117,7 @@ public class YAMLTestWriter extends BaseYAMLTestWriter {
             result.put("type", "library");
             result.put("ectester", ECTesterStandalone.VERSION);
             result.put("name", standaloneSuite.getLibrary().fullName());
+            result.put("seed", ByteUtil.bytesToHex(standaloneSuite.getSeed()));
             return result;
         }
         return null;
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyAgreementTestable.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyAgreementTestable.java
index 579904c..6566a9c 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyAgreementTestable.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyAgreementTestable.java
@@ -5,6 +5,7 @@ import javax.crypto.SecretKey;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
 import java.security.interfaces.ECPrivateKey;
 import java.security.interfaces.ECPublicKey;
 import java.security.spec.AlgorithmParameterSpec;
@@ -17,94 +18,24 @@ public class KeyAgreementTestable extends StandaloneTestable<KeyAgreementTestabl
     private KeyAgreement ka;
     private ECPrivateKey privateKey;
     private ECPublicKey publicKey;
-    private KeyGeneratorTestable kgtPrivate;
-    private KeyGeneratorTestable kgtPublic;
-    private AlgorithmParameterSpec spec;
-    private String keyAlgo;
+    private final KeyGeneratorTestable kgtPrivate;
+    private final KeyGeneratorTestable kgtPublic;
+    private final AlgorithmParameterSpec spec;
+    private final String keyAlgo;
+    private final SecureRandom random;
+
     private byte[] secret;
     private SecretKey derived;
 
-    public KeyAgreementTestable(KeyAgreement ka, ECPrivateKey privateKey, ECPublicKey publicKey) {
-        this.ka = ka;
-        this.privateKey = privateKey;
-        this.publicKey = publicKey;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPrivateKey privateKey, ECPublicKey publicKey, String keyAlgo) {
-        this(ka, privateKey, publicKey);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPrivateKey privateKey, ECPublicKey publicKey, ECParameterSpec spec) {
-        this(ka, privateKey, publicKey);
-        this.spec = spec;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPrivateKey privateKey, ECPublicKey publicKey, ECParameterSpec spec, String keyAlgo) {
-        this(ka, privateKey, publicKey, spec);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable kgt, ECPrivateKey privateKey, ECParameterSpec spec) {
-        this(ka, privateKey, null, spec);
-        this.kgtPublic = kgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable kgt, ECPrivateKey privateKey, ECParameterSpec spec, String keyAlgo) {
-        this(ka, kgt, privateKey, spec);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPublicKey publicKey, KeyGeneratorTestable kgt, ECParameterSpec spec) {
-        this(ka, null, publicKey, spec);
-        this.kgtPrivate = kgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPublicKey publicKey, KeyGeneratorTestable kgt, ECParameterSpec spec, String keyAlgo) {
-        this(ka, publicKey, kgt, spec);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable privKgt, KeyGeneratorTestable pubKgt, ECParameterSpec spec) {
-        this(ka, null, (ECPublicKey) null, spec);
-        this.kgtPrivate = privKgt;
-        this.kgtPublic = pubKgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable privKgt, KeyGeneratorTestable pubKgt, ECParameterSpec spec, String keyAlgo) {
-        this(ka, privKgt, pubKgt, spec);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable kgt, ECPrivateKey privateKey) {
-        this(ka, privateKey, null, (ECParameterSpec) null);
-        this.kgtPublic = kgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable kgt, ECPrivateKey privateKey, String keyAlgo) {
-        this(ka, kgt, privateKey, (ECParameterSpec) null);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPublicKey publicKey, KeyGeneratorTestable kgt) {
-        this(ka, null, publicKey, (ECParameterSpec) null);
-        this.kgtPrivate = kgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, ECPublicKey publicKey, KeyGeneratorTestable kgt, String keyAlgo) {
-        this(ka, publicKey, kgt, (ECParameterSpec) null);
-        this.keyAlgo = keyAlgo;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable privKgt, KeyGeneratorTestable pubKgt) {
-        this(ka, null, (ECPublicKey) null, (ECParameterSpec) null);
-        this.kgtPrivate = privKgt;
-        this.kgtPublic = pubKgt;
-    }
-
-    public KeyAgreementTestable(KeyAgreement ka, KeyGeneratorTestable privKgt, KeyGeneratorTestable pubKgt, String keyAlgo) {
-        this(ka, privKgt, pubKgt, (ECParameterSpec) null);
-        this.keyAlgo = keyAlgo;
+    KeyAgreementTestable(Builder builder) {
+        this.ka = builder.ka;
+        this.privateKey = builder.privateKey;
+        this.publicKey = builder.publicKey;
+        this.kgtPrivate = builder.kgtPrivate;
+        this.kgtPublic = builder.kgtPublic;
+        this.spec = builder.spec;
+        this.keyAlgo = builder.keyAlgo;
+        this.random = builder.random;
     }
 
     public String getKeyAlgorithm() {
@@ -153,9 +84,17 @@ public class KeyAgreementTestable extends StandaloneTestable<KeyAgreementTestabl
             stage = KeyAgreementStage.Init;
             try {
                 if (spec != null) {
-                    ka.init(privateKey, spec);
+                    if (random != null) {
+                        ka.init(privateKey, spec, random);
+                    } else {
+                        ka.init(privateKey, spec);
+                    }
                 } else {
-                    ka.init(privateKey);
+                    if (random != null) {
+                        ka.init(privateKey, random);
+                    } else {
+                        ka.init(privateKey);
+                    }
                 }
             } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
                 failOnException(e);
@@ -197,7 +136,12 @@ public class KeyAgreementTestable extends StandaloneTestable<KeyAgreementTestabl
         super.reset();
         try {
             ka = KeyAgreement.getInstance(ka.getAlgorithm(), ka.getProvider());
-        } catch (NoSuchAlgorithmException e) { }
+        } catch (NoSuchAlgorithmException e) {
+        }
+    }
+
+    public static Builder builder() {
+        return new Builder();
     }
 
     public enum KeyAgreementStage {
@@ -207,4 +151,68 @@ public class KeyAgreementTestable extends StandaloneTestable<KeyAgreementTestabl
         DoPhase,
         GenerateSecret
     }
+
+    public static class Builder {
+        private KeyAgreement ka;
+        private ECPrivateKey privateKey;
+        private ECPublicKey publicKey;
+        private KeyGeneratorTestable kgtPrivate;
+        private KeyGeneratorTestable kgtPublic;
+        private AlgorithmParameterSpec spec;
+        private String keyAlgo;
+        private SecureRandom random;
+
+        public Builder ka(KeyAgreement ka) {
+            this.ka = ka;
+            return this;
+        }
+
+        public Builder privateKey(ECPrivateKey privateKey) {
+            this.privateKey = privateKey;
+            return this;
+        }
+
+        public Builder publicKey(ECPublicKey publicKey) {
+            this.publicKey = publicKey;
+            return this;
+        }
+
+        public Builder privateKgt(KeyGeneratorTestable privateKgt) {
+            this.kgtPrivate = privateKgt;
+            return this;
+        }
+
+        public Builder publicKgt(KeyGeneratorTestable publicKgt) {
+            this.kgtPublic = publicKgt;
+            return this;
+        }
+
+        public Builder spec(AlgorithmParameterSpec spec) {
+            this.spec = spec;
+            return this;
+        }
+
+        public Builder keyAlgo(String keyAlgo) {
+            this.keyAlgo = keyAlgo;
+            return this;
+        }
+
+        public Builder random(SecureRandom random) {
+            this.random = random;
+            return this;
+        }
+
+        public KeyAgreementTestable build() {
+            if (ka == null) {
+                throw new NullPointerException("ka needs to be non-null.");
+            }
+            if ((privateKey == null) == (kgtPrivate == null)) {
+                throw new IllegalStateException("One of (but not both) privateKey or privateKgt needs to be non-null.");
+            }
+            if ((publicKey == null) == (kgtPublic == null)) {
+                throw new IllegalStateException("One of (but not both) publicKey or publicKgt needs to be non-null.");
+            }
+            return new KeyAgreementTestable(this);
+        }
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyGeneratorTestable.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyGeneratorTestable.java
index bc44eb8..f9c84e1 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyGeneratorTestable.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/KeyGeneratorTestable.java
@@ -3,6 +3,7 @@ package cz.crcs.ectester.standalone.test.base;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.KeyPair;
 import java.security.KeyPairGenerator;
+import java.security.SecureRandom;
 import java.security.spec.AlgorithmParameterSpec;
 import java.security.spec.ECGenParameterSpec;
 import java.security.spec.ECParameterSpec;
@@ -15,24 +16,17 @@ public class KeyGeneratorTestable extends StandaloneTestable<KeyGeneratorTestabl
     private final KeyPairGenerator kpg;
     private int keysize = 0;
     private AlgorithmParameterSpec spec = null;
+    private SecureRandom random;
 
     public KeyGeneratorTestable(KeyPairGenerator kpg) {
         this.kpg = kpg;
     }
 
-    public KeyGeneratorTestable(KeyPairGenerator kpg, int keysize) {
-        this.kpg = kpg;
-        this.keysize = keysize;
-    }
-
-    public KeyGeneratorTestable(KeyPairGenerator kpg, ECParameterSpec spec) {
-        this.kpg = kpg;
-        this.spec = spec;
-    }
-
-    public KeyGeneratorTestable(KeyPairGenerator kpg, ECGenParameterSpec spec) {
-        this.kpg = kpg;
-        this.spec = spec;
+    KeyGeneratorTestable(Builder builder) {
+        this.kpg = builder.kpg;
+        this.keysize = builder.keysize;
+        this.spec = builder.spec;
+        this.random = builder.random;
     }
 
     public int getKeysize() {
@@ -57,9 +51,17 @@ public class KeyGeneratorTestable extends StandaloneTestable<KeyGeneratorTestabl
             stage = KeyGeneratorStage.Init;
             try {
                 if (spec != null) {
-                    kpg.initialize(spec);
+                    if (random != null) {
+                        kpg.initialize(spec, random);
+                    } else {
+                        kpg.initialize(spec);
+                    }
                 } else if (keysize != 0) {
-                    kpg.initialize(keysize);
+                    if (random != null) {
+                        kpg.initialize(keysize, random);
+                    } else {
+                        kpg.initialize(keysize);
+                    }
                 }
             } catch (InvalidAlgorithmParameterException e) {
                 failOnException(e);
@@ -78,8 +80,56 @@ public class KeyGeneratorTestable extends StandaloneTestable<KeyGeneratorTestabl
         hasRun = true;
     }
 
+    public static Builder builder() {
+        return new Builder();
+    }
+
     public enum KeyGeneratorStage {
         Init,
         GenKeyPair
     }
+
+    public static class Builder {
+        private KeyPairGenerator kpg;
+        private int keysize = 0;
+        private AlgorithmParameterSpec spec = null;
+        private SecureRandom random;
+
+        public Builder() {}
+
+        public Builder keyPairGenerator(KeyPairGenerator kpg) {
+            this.kpg = kpg;
+            return this;
+        }
+
+        public Builder keysize(int keysize) {
+            this.keysize = keysize;
+            return this;
+        }
+
+        public Builder spec(ECGenParameterSpec spec) {
+            this.spec = spec;
+            return this;
+        }
+
+        public Builder spec(ECParameterSpec spec) {
+            this.spec = spec;
+            return this;
+        }
+
+        public Builder random(SecureRandom random) {
+            this.random = random;
+            return this;
+        }
+
+        public KeyGeneratorTestable build() {
+            if (kpg == null) {
+                throw new NullPointerException("kpg mus be non-null.");
+            }
+            if (spec != null && keysize != 0) {
+                throw new IllegalStateException("Only one of spec and keysize can be set.");
+            }
+            return new KeyGeneratorTestable(this);
+        }
+    }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/SignatureTestable.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/SignatureTestable.java
index 76074e4..5839497 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/SignatureTestable.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/base/SignatureTestable.java
@@ -15,32 +15,32 @@ public class SignatureTestable extends StandaloneTestable<SignatureTestable.Sign
     private ECPrivateKey signKey;
     private ECPublicKey verifyKey;
     private KeyGeneratorTestable kgt;
+    private SecureRandom random;
     private byte[] data;
     private byte[] signature;
     private boolean verified;
 
-    public SignatureTestable(Signature sig, ECPrivateKey signKey, ECPublicKey verifyKey, byte[] data) {
+    public SignatureTestable(Signature sig, ECPrivateKey signKey, ECPublicKey verifyKey, byte[] data, SecureRandom random) {
         this.sig = sig;
         this.signKey = signKey;
         this.verifyKey = verifyKey;
         this.data = data;
-        if (data == null) {
-            SecureRandom random = new SecureRandom();
-            this.data = new byte[64];
-            random.nextBytes(this.data);
-        }
+        this.random = random;
     }
 
-    public SignatureTestable(Signature sig, ECPublicKey verifyKey, byte[] data, byte[] signature) {
+    public SignatureTestable(Signature sig, ECPublicKey verifyKey, byte[] data, byte[] signature, SecureRandom random) {
         this.sig = sig;
         this.verifyKey = verifyKey;
         this.data = data;
         this.signature = signature;
+        this.random = random;
     }
 
-    public SignatureTestable(Signature sig, KeyGeneratorTestable kgt, byte[] data) {
-        this(sig, (ECPrivateKey) null, null, data);
+    public SignatureTestable(Signature sig, KeyGeneratorTestable kgt, byte[] data, SecureRandom random) {
+        this.sig = sig;
         this.kgt = kgt;
+        this.data = data;
+        this.random = random;
     }
 
     public Signature getSig() {
@@ -71,7 +71,11 @@ public class SignatureTestable extends StandaloneTestable<SignatureTestable.Sign
             if(signKey != null) {
                 stage = SignatureStage.InitSign;
                 try {
-                    sig.initSign(signKey);
+                    if (random != null) {
+                        sig.initSign(signKey, random);
+                    } else {
+                        sig.initSign(signKey);
+                    }
                 } catch (InvalidKeyException e) {
                     failOnException(e);
                     return;
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCofactorSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCofactorSuite.java
index 003d510..5079770 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCofactorSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCofactorSuite.java
@@ -56,7 +56,7 @@ public class StandaloneCofactorSuite extends StandaloneTestSuite {
 
             KeyPairGenerator kpg = kpgIdent.getInstance(cfg.selected.getProvider());
             ECParameterSpec spec = curve.toSpec();
-            KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+            KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
 
             Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
@@ -67,7 +67,7 @@ public class StandaloneCofactorSuite extends StandaloneTestSuite {
                     for (EC_Key.Public pub : keys) {
                         ECPublicKey ecpub = ECUtil.toPublicKey(pub);
                         KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                        KeyAgreementTestable testable = new KeyAgreementTestable(ka, ecpub, kgt);
+                        KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).publicKey(ecpub).privateKgt(kgt).random(getRandom()).build();
                         Test keyAgreement = KeyAgreementTest.expectError(testable, Result.ExpectedValue.FAILURE);
                         specificKaTests.add(CompoundTest.all(Result.ExpectedValue.SUCCESS, pub.getId() + " cofactor key test.", keyAgreement));
                     }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCompositeSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCompositeSuite.java
index 38d76bc..d838d20 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCompositeSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneCompositeSuite.java
@@ -64,7 +64,7 @@ public class StandaloneCompositeSuite extends StandaloneTestSuite {
             ECParameterSpec spec = curve.toSpec();
 
             //Generate KeyPair
-            KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+            KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
             Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
             //Perform KeyAgreement tests
@@ -75,7 +75,7 @@ public class StandaloneCompositeSuite extends StandaloneTestSuite {
                     for (EC_Key.Public pub : curveKeys.getValue()) {
                         ECPublicKey ecpub = ECUtil.toPublicKey(pub);
                         KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                        KeyAgreementTestable testable = new KeyAgreementTestable(ka, ecpub, kgt);
+                        KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).publicKey(ecpub).privateKgt(kgt).random(getRandom()).build();
                         Test keyAgreement = KeyAgreementTest.expectError(testable, Result.ExpectedValue.FAILURE);
                         specificKaTests.add(CompoundTest.all(Result.ExpectedValue.SUCCESS, "Composite test of " + curve.getId() + ", with generated private key, " + pub.getDesc(), keyAgreement));
                     }
@@ -133,7 +133,7 @@ public class StandaloneCompositeSuite extends StandaloneTestSuite {
             }
 
             //generate KeyPair
-            KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, curve.toSpec());
+            KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(curve.toSpec()).build();
             Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
             //perform KeyAgreement tests
@@ -141,7 +141,7 @@ public class StandaloneCompositeSuite extends StandaloneTestSuite {
             for (KeyAgreementIdent kaIdent : cfg.selected.getKAs()) {
                 if (kaAlgo == null || kaIdent.containsAny(kaTypes)) {
                     KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                    KeyAgreementTestable testable = new KeyAgreementTestable(ka, kgt, kgt);
+                    KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).publicKgt(kgt).privateKgt(kgt).random(getRandom()).build();
                     kaTests.add(KeyAgreementTest.expectError(testable, dhValue));
                 }
             }
@@ -154,7 +154,8 @@ public class StandaloneCompositeSuite extends StandaloneTestSuite {
             for (SignatureIdent sigIdent : cfg.selected.getSigs()) {
                 if (sigAlgo == null || sigIdent.containsAny(sigTypes)) {
                     Signature sig = sigIdent.getInstance(cfg.selected.getProvider());
-                    SignatureTestable testable = new SignatureTestable(sig, kgt, null);
+                    byte[] data = sigIdent.toString().getBytes();
+                    SignatureTestable testable = new SignatureTestable(sig, kgt, data, getRandom());
                     sigTests.add(SignatureTest.expectError(testable, dhValue));
                 }
             }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneDefaultSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneDefaultSuite.java
index ef9d434..a9b82d5 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneDefaultSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneDefaultSuite.java
@@ -4,6 +4,7 @@ import cz.crcs.ectester.common.cli.TreeCommandLine;
 import cz.crcs.ectester.common.ec.EC_Curve;
 import cz.crcs.ectester.common.output.TestWriter;
 import cz.crcs.ectester.common.test.Result;
+import cz.crcs.ectester.common.util.ECUtil;
 import cz.crcs.ectester.data.EC_Store;
 import cz.crcs.ectester.standalone.ECTesterStandalone;
 import cz.crcs.ectester.standalone.consts.KeyAgreementIdent;
@@ -44,8 +45,8 @@ public class StandaloneDefaultSuite extends StandaloneTestSuite {
         ECParameterSpec spec = null;
         if (cli.hasOption("test.bits")) {
             int bits = Integer.parseInt(cli.getOptionValue("test.bits"));
-            kgtOne = new KeyGeneratorTestable(kpg, bits);
-            kgtOther = new KeyGeneratorTestable(kpg, bits);
+            kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).keysize(bits).build();
+            kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).keysize(bits).build();
         } else if (cli.hasOption("test.named-curve")) {
             String curveName = cli.getOptionValue("test.named-curve");
             EC_Curve curve = EC_Store.getInstance().getObject(EC_Curve.class, curveName);
@@ -54,11 +55,11 @@ public class StandaloneDefaultSuite extends StandaloneTestSuite {
                 return;
             }
             spec = curve.toSpec();
-            kgtOne = new KeyGeneratorTestable(kpg, spec);
-            kgtOther = new KeyGeneratorTestable(kpg, spec);
+            kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).spec(spec).build();
+            kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).spec(spec).build();
         } else {
-            kgtOne = new KeyGeneratorTestable(kpg);
-            kgtOther = new KeyGeneratorTestable(kpg);
+            kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).build();
+            kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).build();
         }
 
         doTest(KeyGeneratorTest.expect(kgtOne, Result.ExpectedValue.SUCCESS));
@@ -69,9 +70,9 @@ public class StandaloneDefaultSuite extends StandaloneTestSuite {
                 KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
                 KeyAgreementTestable testable;
                 if (kaIdent.requiresKeyAlgo()) {
-                    testable = new KeyAgreementTestable(ka, kgtOne, kgtOther, spec, keyAlgo);
+                    testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgtOne).publicKgt(kgtOther).spec(spec).random(getRandom()).keyAlgo(keyAlgo).build();
                 } else {
-                    testable = new KeyAgreementTestable(ka, kgtOne, kgtOther, spec);
+                    testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgtOne).publicKgt(kgtOther).spec(spec).random(getRandom()).build();
                 }
                 doTest(KeyAgreementTest.expect(testable, Result.ExpectedValue.SUCCESS));
             }
@@ -79,7 +80,8 @@ public class StandaloneDefaultSuite extends StandaloneTestSuite {
         for (SignatureIdent sigIdent : cfg.selected.getSigs()) {
             if (sigAlgo == null || sigIdent.contains(sigAlgo)) {
                 Signature sig = sigIdent.getInstance(cfg.selected.getProvider());
-                doTest(SignatureTest.expect(new SignatureTestable(sig, kgtOne, null), Result.ExpectedValue.SUCCESS));
+                byte[] data = sigIdent.toString().getBytes();
+                doTest(SignatureTest.expect(new SignatureTestable(sig, kgtOne, data, getRandom()), Result.ExpectedValue.SUCCESS));
             }
         }
     }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneEdgeCasesSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneEdgeCasesSuite.java
index d441235..12a9f16 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneEdgeCasesSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneEdgeCasesSuite.java
@@ -92,7 +92,7 @@ public class StandaloneEdgeCasesSuite extends StandaloneTestSuite {
                     ECPublicKey ecpub = ECUtil.toPublicKey(EC_Store.getInstance().getObject(EC_Key.Public.class, pubkeyId));
 
                     KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                    KeyAgreementTestable testable = new KeyAgreementTestable(ka, ecpriv, ecpub);
+                    KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKey(ecpriv).publicKey(ecpub).random(getRandom()).build();
                     Test ecdh = KeyAgreementTest.match(testable, value.getData(0));
                     Test one = CompoundTest.all(Result.ExpectedValue.SUCCESS, "Test " + id + ".", ecdh);
                     curveTests.add(one);
@@ -107,7 +107,7 @@ public class StandaloneEdgeCasesSuite extends StandaloneTestSuite {
             ECPrivateKey ecpriv = ECUtil.toPrivateKey(EC_Store.getInstance().getObject(EC_Key.Private.class, openssl_bug.getOtherKey()));
             ECPublicKey ecpub = ECUtil.toPublicKey(EC_Store.getInstance().getObject(EC_Key.Public.class, openssl_bug.getOneKey()));
             KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-            KeyAgreementTestable testable = new KeyAgreementTestable(ka, ecpriv, ecpub);
+            KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKey(ecpriv).publicKey(ecpub).random(getRandom()).build();
             Test ecdh = KeyAgreementTest.function(testable, new TestCallback<KeyAgreementTestable>() {
                 @Override
                 public Result apply(KeyAgreementTestable testable) {
@@ -129,12 +129,12 @@ public class StandaloneEdgeCasesSuite extends StandaloneTestSuite {
                 e.getKey().endsWith("r1") && e.getValue().getField() == javacard.security.KeyPair.ALG_EC_FP).map(Map.Entry::getValue).collect(Collectors.toList());
         curves.add(EC_Store.getInstance().getObject(EC_Curve.class, "cofactor/cofactor128p2"));
         curves.add(EC_Store.getInstance().getObject(EC_Curve.class, "cofactor/cofactor160p4"));
-        Random rand = new Random();
+        Random rand = getRandom();
         for (EC_Curve curve : curves) {
             ECParameterSpec spec = curve.toSpec();
 
             //generate KeyPair
-            KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+            KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
             Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
             //perform ECDH tests
@@ -213,7 +213,7 @@ public class StandaloneEdgeCasesSuite extends StandaloneTestSuite {
         Arrays.sort(zeros);
 
         //generate KeyPair
-        KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+        KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
         Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
         //perform ECDH tests
@@ -247,7 +247,7 @@ public class StandaloneEdgeCasesSuite extends StandaloneTestSuite {
     private Test ecdhTest(KeyGeneratorTestable kgt, BigInteger SParam, ECParameterSpec spec, String desc, Result.ExpectedValue expect) throws NoSuchAlgorithmException {
         ECPrivateKey priv = new RawECPrivateKey(SParam, spec);
         KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-        KeyAgreementTestable testable = new KeyAgreementTestable(ka, kgt, priv);
+        KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKey(priv).publicKgt(kgt).random(getRandom()).build();
         return CompoundTest.all(Result.ExpectedValue.SUCCESS, desc, KeyAgreementTest.expectError(testable, expect));
     }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneForeignSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneForeignSuite.java
index 21431ae..da5d19a 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneForeignSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneForeignSuite.java
@@ -57,9 +57,9 @@ public abstract class StandaloneForeignSuite extends StandaloneTestSuite {
             ECParameterSpec spec = curve.toSpec();
             ECGenParameterSpec namedSpec = new ECGenParameterSpec(curve.getId());
 
-            KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
-            KeyGeneratorTestable kgtOnNamedCurve = new KeyGeneratorTestable(kpg, namedSpec);
-            KeyGeneratorTestable kgtOnDefaultCurve = new KeyGeneratorTestable(kpg, curve.getBits());
+            KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).spec(spec).build();
+            KeyGeneratorTestable kgtOnNamedCurve = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).spec(namedSpec).build();
+            KeyGeneratorTestable kgtOnDefaultCurve = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).keysize(curve.getBits()).build();
 
             // This is some nasty hacking...
             KeyGeneratorTestable theKgt = new KeyGeneratorTestable(kpg) {
@@ -156,7 +156,7 @@ public abstract class StandaloneForeignSuite extends StandaloneTestSuite {
                     for (EC_Key.Public pub : keys) {
                         ECPublicKey ecpub = ECUtil.toPublicKey(pub);
                         KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                        KeyAgreementTestable testable = new KeyAgreementTestable(ka, ecpub, theKgt);
+                        KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).publicKey(ecpub).privateKgt(theKgt).random(getRandom()).build();
                         Test keyAgreement = KeyAgreementTest.expectError(testable, Result.ExpectedValue.FAILURE);
                         specificKaTests.add(CompoundTest.all(Result.ExpectedValue.SUCCESS, pub.getId() + " invalid key test.", keyAgreement));
                     }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneMiscSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneMiscSuite.java
index 657c2ff..87ad0b3 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneMiscSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneMiscSuite.java
@@ -7,6 +7,7 @@ import cz.crcs.ectester.common.test.CompoundTest;
 import cz.crcs.ectester.common.test.Result;
 import cz.crcs.ectester.common.test.Test;
 import cz.crcs.ectester.common.util.ByteUtil;
+import cz.crcs.ectester.common.util.ECUtil;
 import cz.crcs.ectester.data.EC_Store;
 import cz.crcs.ectester.standalone.ECTesterStandalone;
 import cz.crcs.ectester.standalone.consts.KeyAgreementIdent;
@@ -80,7 +81,7 @@ public class StandaloneMiscSuite extends StandaloneTestSuite {
 
     private void testCurve(EC_Curve curve, String catName, KeyPairGenerator kpg, Result.ExpectedValue expected) throws NoSuchAlgorithmException {
         //generate KeyPair
-        KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, curve.toSpec());
+        KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(curve.toSpec()).random(getRandom()).build();
         Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
         //perform KeyAgreement tests
@@ -88,7 +89,7 @@ public class StandaloneMiscSuite extends StandaloneTestSuite {
         for (KeyAgreementIdent kaIdent : cfg.selected.getKAs()) {
             if (kaAlgo == null || kaIdent.containsAny(kaTypes)) {
                 KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                KeyAgreementTestable testable = new KeyAgreementTestable(ka, kgt, kgt);
+                KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).publicKgt(kgt).privateKgt(kgt).random(getRandom()).build();
                 kaTests.add(KeyAgreementTest.expectError(testable, expected));
             }
         }
@@ -101,7 +102,8 @@ public class StandaloneMiscSuite extends StandaloneTestSuite {
         for (SignatureIdent sigIdent : cfg.selected.getSigs()) {
             if (sigAlgo == null || sigIdent.containsAny(sigTypes)) {
                 Signature sig = sigIdent.getInstance(cfg.selected.getProvider());
-                SignatureTestable testable = new SignatureTestable(sig, kgt, hashCurve(curve));
+                byte[] data = sigIdent.toString().getBytes();
+                SignatureTestable testable = new SignatureTestable(sig, kgt, data, getRandom());
                 sigTests.add(SignatureTest.expectError(testable, expected));
             }
         }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandalonePerformanceSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandalonePerformanceSuite.java
index 30a0c0f..46e4141 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandalonePerformanceSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandalonePerformanceSuite.java
@@ -38,9 +38,9 @@ public class StandalonePerformanceSuite extends StandaloneTestSuite {
 
     @Override
     protected void runTests() throws Exception {
-        String kpgAlgo = cli.getOptionValue("test.kpg-type");
-        String kaAlgo = cli.getOptionValue("test.ka-type");
-        String sigAlgo = cli.getOptionValue("test.sig-type");
+        String kpgAlgo = cli.getOptionValue("test.kpg-type", "EC");
+        String kaAlgo = cli.getOptionValue("test.ka-type", "ECDH");
+        String sigAlgo = cli.getOptionValue("test.sig-type", "ECDSA");
         String keyAlgo = cli.getOptionValue("test.key-type", "AES");
 
         List<String> kpgTypes = kpgAlgo != null ? Arrays.asList(kpgAlgo.split(",")) : new ArrayList<>();
@@ -67,8 +67,8 @@ public class StandalonePerformanceSuite extends StandaloneTestSuite {
             KeyPairGenerator kpg = kpgIdent.getInstance(cfg.selected.getProvider());
             if (cli.hasOption("test.bits")) {
                 int bits = Integer.parseInt(cli.getOptionValue("test.bits"));
-                kgtOne = new KeyGeneratorTestable(kpg, bits);
-                kgtOther = new KeyGeneratorTestable(kpg, bits);
+                kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).keysize(bits).random(getRandom()).build();
+                kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).keysize(bits).random(getRandom()).build();
             } else if (cli.hasOption("test.named-curve")) {
                 String curveName = cli.getOptionValue("test.named-curve");
                 EC_Curve curve = EC_Store.getInstance().getObject(EC_Curve.class, curveName);
@@ -77,11 +77,11 @@ public class StandalonePerformanceSuite extends StandaloneTestSuite {
                     return;
                 }
                 spec = curve.toSpec();
-                kgtOne = new KeyGeneratorTestable(kpg, spec);
-                kgtOther = new KeyGeneratorTestable(kpg, spec);
+                kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
+                kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
             } else {
-                kgtOne = new KeyGeneratorTestable(kpg);
-                kgtOther = new KeyGeneratorTestable(kpg);
+                kgtOne = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).build();
+                kgtOther = KeyGeneratorTestable.builder().keyPairGenerator(kpg).random(getRandom()).build();
             }
             kpgTests.add(PerformanceTest.repeat(kgtOne, cfg.selected, kpgIdent.getName(), count));
             kpgTests.add(PerformanceTest.repeat(kgtOther, cfg.selected, kpgIdent.getName(), count));
@@ -94,9 +94,9 @@ public class StandalonePerformanceSuite extends StandaloneTestSuite {
                 KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
                 KeyAgreementTestable testable;
                 if (kaIdent.requiresKeyAlgo()) {
-                    testable = new KeyAgreementTestable(ka, kgtOne, kgtOther, spec, keyAlgo);
+                    testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgtOne).publicKgt(kgtOther).spec(spec).random(getRandom()).keyAlgo(keyAlgo).build();
                 } else {
-                    testable = new KeyAgreementTestable(ka, kgtOne, kgtOther, spec);
+                    testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgtOne).publicKgt(kgtOther).spec(spec).random(getRandom()).build();
                 }
                 kaTests.add(PerformanceTest.repeat(testable, cfg.selected, kaIdent.getName(), count));
             }
@@ -111,10 +111,12 @@ public class StandalonePerformanceSuite extends StandaloneTestSuite {
         for (SignatureIdent sigIdent : cfg.selected.getSigs()) {
             if (sigAlgo == null || sigIdent.containsAny(sigTypes)) {
                 Signature sig = sigIdent.getInstance(cfg.selected.getProvider());
-                sigTests.add(PerformanceTest.repeat(new SignatureTestable(sig, kgtOne, null), cfg.selected, sigIdent.getName(), count));
+                byte[] data = sigIdent.toString().getBytes();
+                sigTests.add(PerformanceTest.repeat(new SignatureTestable(sig, kgtOne, data, getRandom()), cfg.selected, sigIdent.getName(), count));
+                // TODO: The following will always fail as a runTest is not done at this point.
                 if (kgtOne.getKeyPair() != null) {
                     ECPrivateKey signKey = (ECPrivateKey) kgtOne.getKeyPair().getPrivate();
-                    sigTestsNoVerification.add(PerformanceTest.repeat(new SignatureTestable(sig, signKey, null, null), cfg.selected, sigIdent.getName(), count));
+                    sigTestsNoVerification.add(PerformanceTest.repeat(new SignatureTestable(sig, signKey, null, data, getRandom()), cfg.selected, sigIdent.getName(), count));
                 }
             }
         }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneSignatureSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneSignatureSuite.java
index 43feb23..740dca7 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneSignatureSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneSignatureSuite.java
@@ -61,11 +61,11 @@ public class StandaloneSignatureSuite extends StandaloneTestSuite {
 
         byte[] data = sig.getSigData();
         if (data == null) {
-            data = defaultData;
+            data = sigIdent.toString().getBytes();
         }
 
         Signature signature = sigIdent.getInstance(cfg.selected.getProvider());
-        SignatureTestable testable = new SignatureTestable(signature, ecpub, data, sig.getData(0));
+        SignatureTestable testable = new SignatureTestable(signature, ecpub, data, sig.getData(0), getRandom());
         doTest(CompoundTest.all(Result.ExpectedValue.SUCCESS, "ECDSA test of " + sig.getId() + ".", SignatureTest.expectError(testable, expected)));
     }
 }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestSuite.java
index ac164e1..bfea628 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestSuite.java
@@ -3,6 +3,8 @@ package cz.crcs.ectester.standalone.test.suites;
 import cz.crcs.ectester.common.cli.TreeCommandLine;
 import cz.crcs.ectester.common.output.TestWriter;
 import cz.crcs.ectester.common.test.TestSuite;
+import cz.crcs.ectester.common.util.ByteUtil;
+import cz.crcs.ectester.common.util.Util;
 import cz.crcs.ectester.standalone.ECTesterStandalone;
 import cz.crcs.ectester.standalone.consts.Ident;
 import cz.crcs.ectester.standalone.consts.KeyAgreementIdent;
@@ -10,6 +12,7 @@ import cz.crcs.ectester.standalone.consts.KeyPairGeneratorIdent;
 import cz.crcs.ectester.standalone.consts.SignatureIdent;
 import cz.crcs.ectester.standalone.libs.ProviderECLibrary;
 
+import java.security.SecureRandom;
 import java.util.Optional;
 import java.util.Set;
 
@@ -19,17 +22,34 @@ import java.util.Set;
 public abstract class StandaloneTestSuite extends TestSuite {
     TreeCommandLine cli;
     ECTesterStandalone.Config cfg;
+    SecureRandom random;
+    byte[] seed;
 
     public StandaloneTestSuite(TestWriter writer, ECTesterStandalone.Config cfg, TreeCommandLine cli, String name, String... description) {
         super(writer, name, description);
         this.cfg = cfg;
         this.cli = cli;
+        if (cli != null && cli.hasOption("test.prng-seed")) {
+            String seedString = cli.getOptionValue("test.prng-seed");
+            this.seed = ByteUtil.hexToBytes(seedString, true);
+        } else {
+            seed = new SecureRandom().generateSeed(16);
+        }
+        this.random = Util.getRandom(seed);
     }
 
     public ProviderECLibrary getLibrary() {
         return cfg.selected;
     }
 
+    public byte[] getSeed() {
+        return seed;
+    }
+
+    SecureRandom getRandom() {
+        return this.random;
+    }
+
     private <T extends Ident> T getIdent(Set<T> options, String choice, String identName, String defaultChoice) {
         T ident;
         if (choice == null) {
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestVectorSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestVectorSuite.java
index 111d354..1766953 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestVectorSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneTestVectorSuite.java
@@ -56,7 +56,7 @@ public class StandaloneTestVectorSuite extends StandaloneTestSuite {
 
             KeyAgreementIdent kaIdent = KeyAgreementIdent.get("ECDH");
             KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-            KeyAgreementTestable testable = new KeyAgreementTestable(ka, privkey, pubkey);
+            KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKey(privkey).publicKey(pubkey).random(getRandom()).build();
             doTest(CompoundTest.all(Result.ExpectedValue.SUCCESS, "Test vector " + result.getId(), KeyAgreementTest.match(testable, result.getData(0))));
         }
     }
diff --git a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneWrongSuite.java b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneWrongSuite.java
index 4634ab0..1a18188 100644
--- a/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneWrongSuite.java
+++ b/standalone/src/main/java/cz/crcs/ectester/standalone/test/suites/StandaloneWrongSuite.java
@@ -73,11 +73,11 @@ public class StandaloneWrongSuite extends StandaloneTestSuite {
                 String type = curve.getField() == javacard.security.KeyPair.ALG_EC_FP ? "FP" : "F2M";
 
                 //try generating a keypair
-                KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+                KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
                 Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.ANY);
 
                 KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-                KeyAgreementTestable testable = new KeyAgreementTestable(ka, kgt, kgt);
+                KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgt).publicKgt(kgt).random(getRandom()).build();
                 Test ecdh = KeyAgreementTest.expectError(testable, Result.ExpectedValue.FAILURE);
                 doTest(CompoundTest.function(CompoundTest.EXPECT_ALL_SUCCESS, CompoundTest.RUN_ALL_IF_FIRST, "Wrong curve test of " + curve.getBits()
                         + "b " + type + ". " + curve.getDesc(), generate, ecdh));
@@ -96,7 +96,7 @@ public class StandaloneWrongSuite extends StandaloneTestSuite {
         Map<String, EC_Curve> curveMap = EC_Store.getInstance().getObjects(EC_Curve.class, "secg");
         List<EC_Curve> curves = curveMap.entrySet().stream().filter((e) -> e.getKey().endsWith("r1") &&
                 e.getValue().getField() == javacard.security.KeyPair.ALG_EC_FP).map(Map.Entry::getValue).collect(Collectors.toList());
-        Random r = new Random();
+        Random r = getRandom();
         for (EC_Curve curve : curves) {
             short bits = curve.getBits();
             final byte[] originalp = curve.getParam(EC_Consts.PARAMETER_FP)[0];
@@ -233,12 +233,12 @@ public class StandaloneWrongSuite extends StandaloneTestSuite {
 
     private Test ecdhTest(ECParameterSpec spec, String desc) throws NoSuchAlgorithmException {
         //generate KeyPair
-        KeyGeneratorTestable kgt = new KeyGeneratorTestable(kpg, spec);
+        KeyGeneratorTestable kgt = KeyGeneratorTestable.builder().keyPairGenerator(kpg).spec(spec).random(getRandom()).build();
         Test generate = KeyGeneratorTest.expectError(kgt, Result.ExpectedValue.FAILURE);
 
         //perform ECDH
         KeyAgreement ka = kaIdent.getInstance(cfg.selected.getProvider());
-        KeyAgreementTestable testable = new KeyAgreementTestable(ka, kgt, kgt);
+        KeyAgreementTestable testable = KeyAgreementTestable.builder().ka(ka).privateKgt(kgt).publicKgt(kgt).random(getRandom()).build();
         Test ecdh = KeyAgreementTest.expect(testable, Result.ExpectedValue.FAILURE);
         return CompoundTest.function(CompoundTest.EXPECT_ALL_SUCCESS, CompoundTest.RUN_ALL_IF_FIRST, desc, generate, ecdh);
     }